On Wednesday, the developer community will be heading to San Francisco for Chirp, Twitter's new developer conference. But software writers are beginning to wonder whether they still have a role to play in the website's future.

The first signs of unrest came last week, when Fred Wilson, a renowned entrepreneur and Twitter investor, suggested that scores of third-party Twitter clients and services could be rendered obsolete if Twitter decided to incorporate some of those key features – such as URL shortening and photo-sharing – in to its own site.

Then came Twitter's acquisition of Tweetie, one of the most widely used third-party apps, which makes it easy for users to post to their Twitter account from their iPhone. Suddenly, developers wondered whether they even had a business model any more.

Twitter's strategy is a canny one. It has made its application programming interface widely available to the developer community, who have fallen over themselves to jump on the Twitter bandwagon.

Indeed, much of Twitter's success stems from the ecosystem created by these software writers: they have made it possible to automatically shorten web addresses in a tweet to make it easier to stick to the 140 character limit; they have streamlined the process of sharing photos through the microblogging site; they've made it easy for people to manage and keep track of multiple Twitter accounts through their desktop or mobile phone; and have made it possible to search Twitter for trending topics, create and share lists of interesting Twitter users, and even get instant answers to questions.

In the early days, Twitter's key concern was scalability; the website would frequently crash under the weight of traffic, and visitors were greeted with the infamous "fail whale".

Twitter has benefited hugely from focusing money and manpower on addressing this side of the business, and leaving issues of usability and usefulness to innovative developers.

"It was absolutely the right business decision to focus on scalability," says Felix Cohen, technical consultant at Headshift, a social business design consultancy. "The priority was building up the right kind of system, not building out features."

Twitter sees acquisition as the best way of plugging gaps in its functionality. When the need for a real-time search tool became evident, it snapped up Summize; when it decided it needed an "official" app to make it easier for newcomers to engage with Twitter, it bought Tweetie.

In short, cherry-picking the best of the web is a better bet for Twitter than investing directly in building a competing product.

"The developer community has created a vibrant ecosystem around Twitter, but that doesn't mean that every app built using its API is good," says Cohen.

"But those that are doing a good job, who are investing a lot of time, money and effort in to creating useful tools, are certainly doing it in the hope they might get bought by the platform they're developing for."

"I think it's fair to say that developers care more about the people who use their tools to access Twitter than they do about Twitter itself; companies know they have a better chance of being bought if their app dominates the space, and has lots of users and momentum behind it."

Cohen says that the relationship between platforms and developers is constantly evolving. "Developers like to moan about this," says Cohen. "But the truth is that if their app is, in essence, an unpatentable interface idea, then they can't really have any complaints."

But there's no doubt that Twitter faces a difficult couple of days attempting to assuage the concerns of its developer community.

The company will need to be clear about what new features and tools it plans to roll-out itself, and reassure developers that they still have a role to play.

Cohen believes it's highly unlikely that Twitter would start beefing up its web presence at the expense of third-party clients, and has historically been "cautious" when adding new features.

"It was never Twitter's intention to make Twitter.com a destination site," says Cohen. "Even in the early days, people didn't really update their profiles through the site; they used SMS and that's now evolved in to desktop and mobile clients."

In short, then, Twitter will continue to encourage developers to do the heavy lifting for them. Twitter is a relatively small company, by Silicon Valley standards at least, and its focus remains on scaling the business, signing new partnership deals, as it already has with Google and Microsoft, and rolling out localised versions of the service in other countries.

The support of developers will be more crucial than ever as Twitter seeks to turn its obvious potential in to substantial profits.